SPA Physics Theory Lesson

SPA Physics Theory Lesson
2011. August Gui Eng Hong SPA Theory Lesson 2011 Good.ppt Teacher Mr Gui Eng Hong :)

Teacher Mr Gui Eng Hong :)
What is the weightage of SPA in O Level ? P1-MCQ P2 P3 SPA A Marks Marks Marks B Marks Marks Marks C 40 Marks Marks Marks D 50 Marks Marks Marks Teacher Mr Gui Eng Hong :)

There will be a total of _____ assessments (exams) for SPA A one B two C three D four Teacher Mr Gui Eng Hong :)

Measurement – Accuracy A boy uses a metre rule to measure the length of a block of wood. His reading should be _____. A cm B cm C cm D cm Teacher Mr Gui Eng Hong :)

What is wrong with the Measurement shown . . ? L/cm C all should be in 2 decimal places A all should be in in 1 decimal place D all should be in 2 s.f. B all should be in 3 sf Teacher Mr Gui Eng Hong :)

Which is likely to be the Measurement ? L/cm L2/ cm C A L / cm D B L2 / cm2 Teacher Mr Gui Eng Hong :)

Which is likely to be the Calculation ? L/cm L2/ cm C A L / cm D B L2 / cm2 Teacher Mr Gui Eng Hong :)

How should we fill in the calculated value ? L/cm L2/ cm C depends on the s.f. of L A all 3 s.f. D all 2 decimal places B all 2 s.f Teacher Mr Gui Eng Hong :)

What is needed for Measurement & Calculation ? L/cm L2/ cm Measurement Calculation A consistent in d.pl check for number of s.f. B consistent in d.pl consistent in number of s.f. C check for s.f Check for d.pl D consistent in s.f Consistent in d,pl Teacher Mr Gui Eng Hong :)

The radius, R, of a cylinder is measured using a ruler. The radius is 2.3 cm. The cross sectional area of the cylinder is  R2. How should we leave the answer for the area calculated? A cm2 B cm2 C cm2 D 17 cm2 Teacher Mr Gui Eng Hong :)

The radius, R, of a cylinder is measured using a Vernier Calipers. The radius is 2.30 cm. The cross sectional area of the cylinder is  R2. How should we leave the answer for the area calculated? A cm2 B cm2 C cm2 D 17 cm2 Teacher Mr Gui Eng Hong :)

The sides of a box is measured by a ruler. The measurements are 12.0cm x 11.0 cm x 11.0cm. How should we leave the answer for the volume calculated? A cm3 B cm3 C cm3 D Teacher Mr Gui Eng Hong :)

The sides of a box is measured by a ruler. The measurements are 12.0cm x 11.0 cm x 6.0cm. How should we leave the answer for the volume calculated? A cm3 B cm3 C 790 cm3 D 800 cm3 Teacher Mr Gui Eng Hong :)

Which table of measurement is better ? P Q L/cm 4.5 8.9 13.1 14.5 43.4 L/cm 4.5 9.7 20.1 33.5 43.4 Teacher Mr Gui Eng Hong :)

Which table of measurement is better ? R S L/cm 4.5 4.6 4.7 4.8 4.9 L/cm 4.5 6.5 8.5 10.5 13.0 Teacher Mr Gui Eng Hong :)

Which table has the correct heading? M O L / cm L2 / cm 4.5 9.7 20.1 33.5 43.4 L/cm L2 / cm2 4.5 9.7 20.1 33.5 43.4 Teacher Mr Gui Eng Hong :)

Which table has the correct heading? X Y F / N F-1 / N -1 4.5 9.7 20.1 33.5 43.4 F / N F-1 / N 4.5 9.7 20.1 33.5 43.4 Teacher Mr Gui Eng Hong :)

Which table has the correct heading? E F  / o Sin  / o 30 40 50 60 70  / o Sin  30 40 50 60 70 Teacher Mr Gui Eng Hong :)

Which table has correct heading ? R S L1/cm L2 / cm L1L2 -1 / cm L1/cm L2 / cm L1L2 -1 Teacher Mr Gui Eng Hong :)

Best fit line Wrong Teacher Mr Gui Eng Hong :)

Relationship There are two major types A: P is proportional to Q B : P is linearly related to Q Teacher Mr Gui Eng Hong :)

Relationship P is proportional to Q P is linearly related to Q P P Q Q Teacher Mr Gui Eng Hong :)

Difficult Relationship
10 2 P Q 30 9 Teacher Mr Gui Eng Hong :)

Gradient F / N (68.7, 0.48) IMPORTANT Show Triangle Triangle must be big Show Coordinate Show working Calculate gradient  3 sf 0.5 0.4 0.3 0.2 0.1 (18.5, 0.09) 10 20 30 40 50 60 Q / cm Teacher Mr Gui Eng Hong :)

Axes F / N IMPORTANT Label with units Choose scale such that graph is BIG Graph must be tall (>1/2) Graph must be wide (>1/2) avoid weird / inconvenient scales (wrong ! 30 squares = 1.0 N ) Choose scales involving 2,4,5,10 (68.7, 0.48) 0.5 0.4 0.3 0.2 0.1 (18.5, 0.09) 10 20 30 40 50 60 Q / cm Graph paper Teacher Mr Gui Eng Hong :)

A SAMPLE OF GRAPH DONE CORRECTLY F / N 2.0 (2.5,1.9) 1.5 1.0 0.5 (0.875,0.30) Tan β 0.0 0.5 1.0 1.5 2.0 2.5 Teacher Mr Gui Eng Hong :)

Table of recording L1/cm L2 / cm L1L2 -1  / o Sin  Must have correct way of heading and units (if any) At least five sets of data Teacher Mr Gui Eng Hong :)

avoid silly graph plotting/reading mistake
5 6 3.1 3.2 (3.13, 5.4) correct ! wrong ! Teacher Mr Gui Eng Hong :)

Source of Error and its effect
Must state how the SOE affect the experiment Cannot be something superficial – there is wind cannot see clearly Must be something hard to avoid even if you try Teacher Mr Gui Eng Hong :)

Example : The mass of string is not included in the calculation, affectting the accuracy of LY measured. Example : The image becomes dim at the range of object distance between 15.0 cm and 30.0cm, unable to find the focus the image very sharply, affects the accuracy of V measured. BAD example : unable to find image, experiment inaccurate Teacher Mr Gui Eng Hong :)

Example : Very hard to maintain ensure that the spring balance is kept horizontal. Affects the accuracy of F2. Example : The plumbline moves a bit when the protractor touches it, unable to measure the angle very accurately. Affects the accuracy of  Teacher Mr Gui Eng Hong :)

plotting of points must be very accurate ! point (21.6 , 3.0)
2.0 2.0 21 22 21 22 Teacher Mr Gui Eng Hong :)

Sites.google.com/site/guienghong Revision PowerPoints
SPA Self Revision 2011 Sites.google.com/site/guienghong Revision PowerPoints Teacher Mr Gui Eng Hong :)

Precision of Instrument
Ruler Which is correct ? A) L = 23 cm B) L = 23.0 cm C) L = cm Teacher Mr Gui Eng Hong :)

Ruler Which is correct ? A) L = 23 cm B) L = 23.0 cm  C) L = cm Teacher Mr Gui Eng Hong :)

Protractor Which is correct ? A) θ = 23o B) θ = 23.0 o C) θ = o Teacher Mr Gui Eng Hong :)

Protractor Which is correct ? A) θ = 23o  B) θ = 23.0 o C) θ = o Teacher Mr Gui Eng Hong :)

Stop-Watch Which is correct ? A) L = s B) L = 11.3 s C) L = 11 s Teacher Mr Gui Eng Hong :)

Stop-Watch Which is correct ? A) L = s  B) L = 11.3 s C) L = 11 s Teacher Mr Gui Eng Hong :)

Spring Balance Which is correct ? A) F = 1.2N B) F = 1.20N C) F = 1.200N Teacher Mr Gui Eng Hong :)

Spring Balance Which is correct ? A) F = 1.2N B) F = 1.20N  C) F = 1.200N Teacher Mr Gui Eng Hong :)

Electronic Balance Which is correct ? A) M = 25 g B) M = 25.0 g C) M = 25.00g Teacher Mr Gui Eng Hong :)

Electronic Balance Which is correct ? A) M = 25 g B) M = 25.0 g C) M = 25.00g  Teacher Mr Gui Eng Hong :)

Measuring Cylinder Which is correct ? A) V = 53 cm3 B) V = 53.0 cm3 C) V = cm3 Teacher Mr Gui Eng Hong :)

Measuring Cylinder Which is correct ? A) V = 53 cm3 B) V = 53.0 cm3 C) V = cm3 Teacher Mr Gui Eng Hong :)

Therometer Which is correct ? A) T = 24 o B) T = 24.0 o  C) T = o Teacher Mr Gui Eng Hong :)

Volmeter Which is correct ? A) V = 1.2V B) V = 1.20V  C) V = 1.200V Teacher Mr Gui Eng Hong :)

Ammeter Which is correct ? A) I = 0.2A B) I = 0.20A  C) I = 0.200A Teacher Mr Gui Eng Hong :)

Table Which is correct ? L (cm) L / cm L – cm Teacher Mr Gui Eng Hong :)

Table correct ! L / cm Teacher Mr Gui Eng Hong :)

Table Which is correct ? 1/L 1/L / 1/cm L-1 / cm-1 Teacher Mr Gui Eng Hong :)

Table correct ! L-1 / cm-1 Teacher Mr Gui Eng Hong :)

Table Sample F / N L / cm L-1 / cm-1 0.30 5.0 2 sf 0.80 20.0 3 sf 1.20 35.0 1.45 45.0 1.70 60.0 Teacher Mr Gui Eng Hong :)

Table Sample F / N F2 / N2 L / cm L-1 / cm-1 0.30 2 sf 5.0 0.80 20.0 3 sf 1.20 35.0 1.45 45.0 1.70 60.0 Teacher Mr Gui Eng Hong :)

Table Sample  / o sin  30 2 sf 40 50 65 70 Teacher Mr Gui Eng Hong :)

Table Range too small  / o sin  30 2 sf 35 40 45 50 Teacher Mr Gui Eng Hong :)

Table Range Correct  / o sin  20 2 sf 30 40 50 60 70 Range must be as big as possible , spreading out values of independent variable as far as possible Teacher Mr Gui Eng Hong :)

Table Range too small L / cm L2 / cm2 30.0 3 sf 32.0 34.0 36.0 38.0 Teacher Mr Gui Eng Hong :)

Table Range OK ! L / cm L2 / cm2 15.0 3 sf 30.0 45.0 60.0 75.0 90.0 Range must be as big as possible , spreading out values of independent variable as far as possible Teacher Mr Gui Eng Hong :)

Graph Axis F/N L/cm T / s F-1 / N-1 Tan  Teacher Mr Gui Eng Hong :)

Graph Use sharp pencil for Graph Use a Long 30cm transparent ruler to best fit line Teacher Mr Gui Eng Hong :)

Graph Scale 10 Squares : 0.20 N 10 squares : 5 cm Must be > ½ Graph paper Vertically Must be > ½ Graph paper Horizontally Use sharp pencil for Graph Use a Long 30cm transparent ruler to best fit line Do NOT use 3, 6, 7, 9 Teacher Mr Gui Eng Hong :)

Gradient Triangle must be BIG Show coordinates of the two points Draw dotted lines for Triangle Leave Answer of Gradient in 3 s.f. Use sharp pencil for Graph Use a Long 30cm transparent ruler to best fit line Teacher Mr Gui Eng Hong :)

Gradient (1.22, 67.5) (0.10, 8.5) Show working on how gradient is determined / calculated Leave gradient in 3 sf Teacher Mr Gui Eng Hong :)

Best Fit Line (A) – wrong
Teacher Mr Gui Eng Hong :)

Best Fit Line (A) – Correct

Best Fit Line (B) – wrong

Best Fit Line (B) – Correct

A SAMPLE OF GRAPH DONE CORRECTLY F / N 2.0 (2.5,1.9) 1.5 1.0 0.5 (0.875,0.30) Tan β 0.0 0.5 1.0 1.5 2.0 2.5 Teacher Mr Gui Eng Hong :)

SPA Physics Theory Lesson

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